I have a hardcover book that is pretty thick and has smudges of something on the edges. It really looks like someone handled the book with dirty fingers. I wonder if there is a good way to remove it. It is also a bit warped (twisted). I'm wondering if it's postable or if I can 'fix' it so it can be posted. 

Thanks.

Some members have reported success using fine sandpaper with a light touch, but I've never tried it myself.  Good luck!

I use fine grade sandpaper to clean up lightly soiled page edges. Hold the pages together and rub lengthwise with the pages, not across them.

For the twisted spine. You can try twisting them back into place and using something to clamp the book or set it under something really heavy. I think it would take a bit of time for the spine to hold so you'd probably want to leave it that way for a couple of weeks. 

Another thing that I've tried with spines that are not severely twisted is to open the book a little ways into it, make sure the spine is set straight, and then rub up and down in the crack of the pages. Repeat that every so often after a small chunk of pages and that can help straighten out a spine too.